Lagoa de Santo André (S Portugal): phytopigments as sedimentary tracers

Abstract

During the last years, the study of chorophyll a and its derivatives is increasingly used in the understanding of productivity phenomena of aquatic sediments. St . André is a coastal brackish lagoon , with large amounts of organic matter in the surface sediments.This paper deals with phytopigments, organic matter (loss on ignition), water content and granulometry of the sediments. Two distinct zones of productivity are closely related with the main sediment types: sands and muds. Phaeopigments correlate well with organic matter emphasizing its vegetal origin. Muds present a larger pigment concentration but it seems that also in the sandy zone production prevails over sedimentary processes.